1. Field of the Invention
The present invention relates to a semiconductor wafer which has a support plate adhered to one or front surface thereof in the form of a flat surface with a semiconductor circuit formed thereon, and of which the other or rear surface is partially removed to reduce its thickness, and it also relates to a semiconductor device manufactured by using the semiconductor wafer as well as to a method of manufacturing semiconductor devices.
2. Description of the Related Art
In the past, there has been known a method for manufacturing semiconductor devices in which a support plate for reinforcing the mechanical strength of a semiconductor wafer is first attached or adhered to a flat front surface of the semiconductor wafer having a semiconductor circuit formed thereof, and then an opposite rear surface of the semiconductor wafer is partially removed to reduce its thickness, thereby providing the semiconductor devices. Such a method of manufacturing semiconductor devices is disclosed in Japanese patent application laid-open No. H10-335195, for example.
In this case, however, it is necessary to grind the rear surface of the semiconductor wafer to reduce the initial thickness thereof to about 1/10 thereof, and hence there arises the following problem.
That is, in general, semiconductor wafers having cleavage are highly brittle and are single crystal, so they are rapidly becoming easier to crack in accordance with the decreasing thickness thereof. Thus, it is extremely difficult to convey or transport the semiconductor wafers after they have been ground to a certain thickness or less. Therefore, each semiconductor wafer is attached or adhered to a support plate of a prescribed rigidity before grinding thereof. In this case, however, support plates adhered to semiconductor wafers, respectively, are made to have the same diameter as that of the semiconductor wafers adhered thereto due to the necessity of using in common the wafer conveyance or transportation system of processing equipment before and after the grinding of the rear surface of each semiconductor wafer. If, however, for instance, both of a semiconductor wafer and a support plate have a maximum amount of tolerance, the overall outside diameter of the semiconductor wafer and the support plate after adhered to each other will be increased by a positioning or registering error therebetween which would be generated upon adhering the support plate to the semiconductor wafer, so that it might become larger than an allowed entire outside diameter, thus resulting in difficulty in the handling thereof by a conveyance or transportation system of post-processing equipment. To avoid such a situation, there arises the following problem. That is, for instance, it is necessary to prepare jigs, attachments, etc., suited to fit the combined wafer and support plate into respective processing apparatuses, and in addition, it is also necessary to use or replace such jigs and attachments in individual cases, thus reducing the manufacturing efficiency.
Moreover, when the semiconductor wafer actually protrudes from the corresponding support plate, the protruded portion of the wafer is very easy to crack and would be causes of resultant defects and/or contamination, and hence the protruding of the semiconductor wafer from the support plate is not allowed in fact. As a result, extremely high accuracies are required in terms of the individual dimensions of the semiconductor wafer and the support plate as well as the total size or adhering positions thereof when they are adhered to each other.